Sealed contact device



Oct. 2, 962 B. DAL BIANCO ETAL 3,

SEALED CONTACT DEVICE Filed April 28, 1960 Inventor Bruno Dal Bianca MScata B' W? United States Patent Ofifice 3,056,869 Patented Oct. 2, 19623,056,869 SEALED CGNTACT DEVICE Bruno Dal Bianco, Milan, and MarioScata, Monza, Italy,

assignors to International Standard Electric Corporation, New York,N.Y., a corporation of Delaware Fiied Apr. 28, 1960, Ser. No. 25,437Claims priority, application Italy June 17, 1959 Claims. (Cl. 200-87)This invention relates to electromagnetically or magnetically operatedmake and break electrical contact devices, and particularly to make andbreak contacts of the type enclosed in a protective vessel in which themechanical elements, subjected to a magnetic field, are used also asmembers conveying the current to the contact points.

Devices of this kind generally comprise a small glass tube, at the endsof which are sealed magnetic material Wires or small bars. The tube iseither air evacuated or filled with an inert gas. In these prior-artdevices, the ends of the two magnetic wires inside the glass tube areoverlapped with a small air gap therebetween. The tube is generally putinside an electromagnetic coil which, when current flows through itswinding, causes the two wires to contact each other, closing an externalelectric circuit connected thereto.

One of the features of the present invention is to provide an improveddevice of the type described which gives economical advantages andsimplicity in fabrication, is easy to put into operation and designed tobe used for various purposes depending upon the number of contactelements placed inside the vessel.

A further object of the invention is the production of a strong deviceof very small size, easy to be replaced, and which is based on theprinciples disclosed in our copending US. patent application No.722,194, filed March 18, 1958.

One of the main objects of the invention is the fabrication of a controldevice for electrical circuits, which is not integral with theenergizing coil and which has, in most cases, the magnetic structuresealed to the container by one end only permitting easy assembly onprinted circuits.

A further feature of the invention is that, in the manufacture andadjustment of the mechanical structure of the device, all pieces areworked outside the protective vessel, and then sealed thereinto byautomatic means requiring no particular arrangement or jig to adjust thecontact gap, the latter being adjusted when the structure touches theclosed end of the container before the sealing operation.

Another object of the invention is to provide a switch structure which,by slight variations, can be modified from a simple circuit maker andbreaker to a multi contact changeover switch.

A short description will now be given for the better understanding ofthe scope of the present invention as illustrated in the variousembodiments shown in the accompanying drawings, in which:

FIG. 1 shows, on an enlarged scale, a sectional view of the switchingunit of the inventive switch structure.

FIG. 2 shows a complete switch structure comprising the switching unitof FIG. 1 and an associated flux generating core and winding.

FIG. 3 illustrates, a sectional view of the switching unit of FIG. 1,modified to provide a multi-contact changeover relay.

FIG. 4 illustrates, on an enlarged scale, an alternative of the contactstructure in which the armature is formed by a disc free to rotate aboutits guiding axis.

FIG. 5 shows, on an enlarged scale, a section view of the contact deviceof FIG. 4 in which two electrodes are added to provide a sequence ofswitching operations.

FIG. 6 shows, on an enlarged scale, a sectional view of a furtherarrangement of the movable armature inside the vessel.

FIG. 7 shows an end sectional view of the device illustrated in FIG. 6,to show the operation of the movable armature of the device.

The sealed electric contact device of FIG. 1 comprises a small vessel 1,generally of glass and of cylindrical shape, the size of which could be5 x 10 mm. At one end of the vessel there are sealed the electricalcontact elements, forming a magnetic structure which comprises aU-shaped thick wire 2. On two ends 3 and 4 of the U-shaped wire 2, athird piece of wire 5 of very good magnetic material is bridged across.The bridge piece or armature is electrically connected to one of thearms 3 or 4 of the U-shaped wire 2 by means, for example, of a flatspring 6, welded near the end of arm 3 and to one end of the bridgepiece 5. Spring 6 urges armature 5 away from arm 4. Upon theintroduction of the magnetic structure into the vessel, spring 6 isloaded when the top of the structure touches the bottom of vessel 1, toobtain the wanted gap between the open contacts of the relay. Aftersealing the arms 3-4 to end 7 of vessel 1, the base of the U-shaped wire2, which is generally larger than the separation of the branches sealedinto the vessel, is cut along the line a-a, and the device is now readyto be connected to the circuit of FIG. 2.

It is evident that the bridge piece 5 and its supporting seats could bemade with various shapes other than the flat one without therebyaffecting the operational conditions of the magnetic structure.

The ends of bridge piece 5 in contact with the ends 34 of the U barcould be coated with a suitable metal of good electrical conductivity.

FIG. 2 illustrates schematically the way in which to insert the sealedcontact device into the energizing structure. The magnetic contactcarrier structure or switching unit, after the U base cutting, willprovide two terminal lugs 8 and 9 which, when inserted between polepieces NS of an open magnetic circuit M, will complete a magneticcircuit through the movable armature 5 enclosed in vessel 1. The mainadvantage of this arrange ment is that the length of the mean turn ofthe energizing coil 10 is brought to a minimum depending only upon thediameter of the core forming the magnetic circuit M. This providesadvantages from the point of view of the magnetic force obtainable andfor the small size of the energizing coil.

This arrangement also permits a great number of applications and an easyreplacement possibility of the contact structure.

In FIG. 3 there is illustrated the contact device of FIG. 1 suitable toperform a switching of electrical circuits. In this case bridge piece 5through the effect of spring 6 is strongly pressed against thestationary contact 11, sealed to the other end of vessel 1.

The adjustment of the gap between the end of bridge piece 5 and the topof bar 4 is made as soon as the magnetic structure is put into thevessel 1, before arms 34are sealed to the container.

In FIG. 4 there is illustrated a constructional alternative of FIG. 1 inwhich bridge piece 5 is replaced by a disc 12 of magnetic material ofgood property. The disc 12 is kept by a spindle 13, L-shaped or by othermeans soldered to one of the arms 3 or 4. The disc 12 is free to rotateon said spindle 13 and is urged upwards by a cylindrical spring 14. Astop 15 prevents the disk from leaving axis 13.

It will be understood that by this arrangement the face of the discwhich comes in contact with the ends of bars 34 continually changes itsown position with respect to these bars, for each attraction, withconsiderable advantages when closing the circuit connected to bars 3-4.

In FIG. 5 there is illustrated the same arrangement of FIG. 4 modifiedto obtain a changeover switch. In this case disc 12 has both facesadapted to make a very .good electrical contact when urged against thetop of the rods of another U-shaped piece 16 of non-magnetic material,sealed to the other end of vessel 1 and when attracted against the endsof bars 3-4, to make a work contact.

In FIGS. 6 and 7 there is illustrated a further shape which can be givento the sealed contact elements of the relay.

As seen in the side view of the vessel shown in FIG. 6, an extension 17of a leaf 18 of very good magnetic material is mechanically andelectrically secured to one of the arms 3 or 4.

Leaf 18, as seen in the end view of FIG. 7, while having one of itssides in close contact with arm 3, has the other side slightly spacedfrom arm 4. The surfaces which come in contact between arm 4 and oneside of the leaf 18 are provided with coatings of metal .of goodelectrical conductivity. It must be noted that due to the cylindricalform of container 1, leaf 18 will find a natural rest position over theinternal wall of the glass tube which will define the rest position ofleaf 18.

From the foregoing it will be clear that the novel form given to thecontact device in the various examples previously illustrated, willpermit a number of applications especiallyin the switching field, itbeing possible to embody switches and multiswitches for step-by-step andcrossbar systems.

It is to be understood that the devices described above are examplesembodying the principles of the present invention. A number of otherdevices could be designed by those skilled in the art without departing,however, from the spirit and the scope of the present invention.

What is claimed is:

1. A magnetically operated switch structure comprising a switching unithaving first and second spaced parallel bars of magnetic material and aco-operating armature of magnetic material positioned in flux-linkingrelationship therewith, means for electrically connecting one end ofsaid armature to said first bar and for supporting the other end of saidarmature for movement to selectively make and break an electricalconnection between said armature and said second bar, the saidsupporting means urging the said armature away from said second bar, anenclosing envelope within which said armature and a portion of said barsare enclosed with the other portion of said bars extending externallyout of one end of said envelope and sealed therethrough in avacuum-tight manner and with the said armature being positioned withrespect to the other end of said envelope to abut thereagainst when theswitch is in an unoperated state to provide a desired air gap betweenthe said armature and said second bar, and a magnetic flux generatingunit comprising an open-ended core having a flux-generating windingthereon with the ends of said core in flux-linking relationship with thesaid external portions of said bars.

2. A magnetically operated switch structure as set forth in claim 1wherein the said means for movably supporting said armature includesmeans for positioning the said armature substantially at'right angles tothe longitudinal axis of said pair of bars.

3. A magnetically operated switch structure as set forth in claim 1wherein the magnetic material in said pair of bars and said armature isnon-flexible.

4. A magnetically-operated switch structure as set forth in claim 1wherein the said abutting portion of the said envelope includes anelectrical conductor normally in electrical contact with said armatureand the said first bar of said pair of bars.

5. A magnetically operated switch structure as set forth in claim 1wherein the cross-sectional area of said core is less than thecross-sectional area of said envelope.

References Cited in the file of this patent UNITED STATES PATENTS684,378 Potter Oct. 8, 1901 1,085,810 Hoge Feb. 3, 1914 2,483,723 BurtonOct. 4, 1949 2,732,451 Degler Jan. 24, 1956 2,834,847 Jennings May 13,1958 2,834,848 Ellwood May 13, 1958 2,908,780 Walters Oct. 13, 19592,912,539 Jennings Nov. '10, 1959 2,916,579 Kesselring et al. Dec. 8,1959

